DESCRIPTION OF SPECIES— CDPULIFER^. 145 



always rough; the secondary veins and their divisions are traced deep into the 

 derm, and the nervilles are also deep and distinct, though the details of areola- 

 tion are rarely so. It is always difficult, in our specimens at least, to recognize 

 the triple denticulation of the borders, the teeth sometimes appearing simple, 

 and being generally more or less destroyed or erased. 



Habitat. — Carbon Station, Wyoming; Washakie group {Dr. F. V. 

 Hayden). I have not seen as yet any specimens of the species from the 

 Upper Miocene of Green River and the Parks. Those from the Lower 

 Lignitic are indistinct and scarcely determinable. 



FAGUS, Toumf. 



One of the more clearly defined generic types of the Cretaceous Dakota 

 group flora is that of Fagus. Two species, described from leaves (they 

 may, however, represent one only), have been published from this formation, 

 Fagus polydada (Lesqx., Report of the U. S. Geol. Surveys of the Territo- 

 ries, vol. vi, p. 67, pi. V, fig. 6) and F. cretacea (Newby., Notes on the Later 

 Extinct Floras of N. A., p. 23). From this it seems that a genus whose origin 

 is recognized in the Cretaceous, and which, by the wide distribution of one 

 of its species at the present time through the eastern slope of the North 

 American continent, furnishes one of the principal constituents of its forests, 

 should have left its traces through the intermediate geological formation 

 by an abundance of its fossil remains. As yet, it is not the case. No posi- 

 tively determinable fossil leaves referable to Fagus have been observed in the 

 Lower Lignitic of the Rocky Mountains, and none either in the higher stage 

 of the Eocene at Evanston or in the Miocene of Carbon. The species 

 described here below as Fagus Feronice is from the Upper Tertiary (Miocene) 

 of the Rocky Mountains, and even, as it may be seen from the remarks in 

 the description, it is not certain that the leaves referred to it truly belong 

 to this genus. We have to go higher still in the Tertiary formations, or in 

 the Pliocene of the Chalk Bluffs of California, to find vegetable remains as 

 distinctly identifiable with Beech as are those of the Cretaceous. This may 

 seem a strange inconsistency of distribution. It may be accounted for, as in 

 other analogous cases, by our insufficient acquaintance with the geological 

 floras of this continent, represented as they still are by comparatively scanty 

 materials. The proof is, that fruits of Fagus, perfectly similar to those of 

 the living species, have been found in the Lower Lignitic of Tennessee and 



10 T F 



